Method and apparatus for keying a digital video signal
US5043800A · kind A · utility
4Cited by
2References
16Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 14, 1989 |
| Grant date | Aug 27, 1991 |
| Priority date | — |
| Expiry date | Sep 14, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/2622
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for keying digital color TV signals to avoid "stairstepping" of pixels at the edges of the key while retaining a hard switch between the keyed scenes. This is achieved by comparing successive digital keying signals with a desired digital clip level. In the event that the clip level occurs between two successive digital signals an interpolation of the clip level between these is created fractionally. A digital representation of this fraction is then included in the keying signal so that keying is accomplished on a sub-pixel basis without acutally increasing the frequency of sampling.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.